核苷(酸)类似物抗病毒治疗慢性重型乙型肝炎的疗效观察

目的 评价核苷(酸)类似物抗病毒治疗慢性重型乙型肝炎的疗效.方法 治疗组65例慢性重型乙型肝炎患者在内科综合治疗基础上加用核苷(酸)类似物抗病毒治疗,对照组63例慢性重型乙型肝炎患者只采用内科综合治疗,比较2组血清总胆红素(TBil)、丙氨酸氨基转移酶(ALT)、凝血酶原活动度(PTA)、乙肝病毒DNA(HBV-DNA)水平和病死率.结果 治疗1个月后2组PTA高于治疗前,但2组升高水平比较差异无统计学意义(P>0.05);2组TBil、ALT和HBV-DNA水平均低于治疗前,但2组降低水平比较差异无统计学意义(P>0.05);治疗组死亡6例(9.2%),对照组死亡6例(9.5%),2组比较差异无统计学意义(P>0.05).治疗3个月后2组PTA均高于治疗前,且治疗组高于对照组,差异均有统计学意义(P<0.05);2组TBil、ALT和HBV-DNA水平均低于治疗前,差异有统计学意义(P<0.05);治疗组死亡8例(12.3%),对照组死亡17例(27.0%),2组比较差异有统计学意义(P<0.05).结论 核苷(酸)类似物抗病毒治疗慢性重型乙型肝炎3个月后,可以明显降低乙肝病毒DNA(HBV-DNA)水平,改善肝功能,降低病死率.     

核苷（酸）类似物抗病毒治疗慢性重型乙型肝炎的疗效观察

目的评价核苷（酸）类似物抗病毒治疗慢性重型乙型肝炎的疗效。方法治疗组65例慢性重型乙型肝炎患者在内科综合治疗基础上加用核苷（酸）类似物抗病毒治疗,对照组63例慢性重型乙型肝炎患者只采用内科综合治疗,比较2组血清总胆红素（TBil）、丙氨酸氨基转移酶（ALT）、凝血酶原活动度（PTA）、乙肝病毒DNA（HBV-DNA）水平和病死率。结果治疗1个月后2组PTA高于治疗前,但2组升高水平比较差异无统计学意义（P〉0.05）;2组TBil、ALT和HBV-DNA水平均低于治疗前,但2组降低水平比较差异无统计学意义（P〉0.05）;治疗组死亡6例（9.2%）,对照组死亡6例（9.5%）,2组比较差异无统计学意义（P〉0.05）。治疗3个月后2组PTA均高于治疗前,且治疗组高于对照组,差异均有统计学意义（P〈0.05）;2组TBil、ALT和HBV-DNA水平均低于治疗前,差异有统计学意义（P〈0.05）;治疗组死亡8例（12.3%）,对照组死亡17例（27.0%）,2组比较差异有统计学意义（P〈0.05）。结论核苷（酸）类似物抗病毒治疗慢性重型乙型肝炎3个月后,可以明显降低乙肝病毒DNA（HBV-DNA）水平,改善肝功能,降低病死率。     

乙型肝炎病毒对核苷(酸)类似物耐药的研究进展

在过去10余年里,口服核苷（酸）类似物的应用使慢性乙型肝炎的治疗取得很大进展。长期核苷（酸）类似物治疗的主要缺陷是乙型肝炎病毒（HBV）耐药性的产生,后者可致所获得的疗效丢失,有时可导致肝炎活动、甚至死亡。本文主要介绍HBV耐药的发生机制、相关定义、发生率、处理及预防策略等。     

核苷类抗乙肝病毒药物研究近况

主要根据 2 0 0 1年 11月 9～ 13日在美国德州达拉斯市召开的第 5 2届美国肝病学年会的内容对新一代核苷类抗乙肝病毒的药物作一介绍。在这次会议上报告了 7种新的核苷类抗乙肝药 ,已分别进入Ⅰ期 ,Ⅱ期和Ⅲ期临床试验阶段 ,其中阿德福韦、恩替卡韦和依曲西他平已在作Ⅲ期临床。但是阿得福韦的肾毒性 ,恩替卡韦的长期安全性和依曲西他平与拉米夫定的交叉耐药性在正式批准临床应用阶段需作进一步的观察。本文还阐述了核苷类药物结构与抗病毒活性的关系 ,介绍了药物对病毒复制动力学影响在研究药物作用中的意义     

The main hepatitis B virus (HBV) mutants resistant to nucleoside analogs are susceptible in vitro to non-nucleoside inhibitors of HBV replication

Long-term treatment of chronic hepatitis B with nucleos(t)ide analogs can lead to the emergence of HBV resistant mutants of the polymerase gene. The development of drugs with a different mode of action is warranted to prevent antiviral drug resistance. Only a few non-nucleosidic molecules belonging to the family of phenylpropenamides (AT-61 & AT-130) and heteroaryldihydropyrimidines (BAY41-4109) can prevent RNA encapsidation or destabilize nucleocapsids, respectively. The sensitivity of the main nucleos(t)ide analog- resistant mutants to these inhibitors was evaluated in vitro. HepG2 stable cell lines permanently expressing wild type (WT) HBV or the main HBV mutants resistant to lamivudine and/or adefovir (rtL180M + rtM204V, rtV173L + rtL180M + rtM204V, rtM204I, rtL180M + rtM204I, rtN236T, rtA181V, rtA181V + rtN236T, rtA181T, rtA181T + rtN236T) were treated with AT-61, AT-130 or BAY-41 4109. Analysis of intracellular encapsidated viral DNA showed that all mutants were almost as sensitive to these molecules as WT HBV; indeed, the fold-resistance ranged between 0.7 and 2.3. Furthermore, the effect of a combination of either AT-61 or AT-130 with BAY41-4109, and the combination of these compounds with tenofovir was studied on wild type HBV as well as on a lamivudine and an adefovir-resistant mutant (rtL180M + M204V and rtN236T, respectively). These combinations of compounds resulted in inhibition of viral replication but showed slight antagonistic effects on the three HBV species. Based on this in vitro study, BAY-41 4109, AT-61 and AT-130 molecules that interfere with capsid morphogenesis are active against the main lamivudine- and adefovir-resistant mutants. These results suggest that targeting nucleocapsid functions may represent an interesting approach to the development of novel HBV inhibitors to prevent and combat drug resistance.     

核苷（酸）类似物用于透析患者合并乙型肝炎的治疗

维持性血液透析(血透)患者乙型肝炎病毒(HBV)感染率明显高于健康人群和慢性肾脏病非透析患者.透析患者HBV感染症状多较轻微但易出现慢性化进展,针对此类病例抗病毒治疗依然是关键.本文重点就抗病毒药物核苷(酸)类似物用于血透患者合并乙型肝炎治疗作一综述.     

Synthesis and antiviral activity of novel acyclic nucleoside analogues of 5-(1-azido-2-haloethyl)uracils.

We present the discovery of a novel category of 5-substituted acyclic pyrimidine nucleosides as potent antiviral agents. A series of 1-[(2-hydroxyethoxy)methyl] (5-7), 1-[(2-hydroxy-1-(hydroxymethyl)ethoxy)methyl] (8-10), and 1-[4-hydroxy-3-(hydroxymethyl)-1-butyl] (11-13) derivatives of 5-(1-azido-2-haloethyl)uracil were synthesized and evaluated for their biological activity in cell culture. 1-[4-Hydroxy-3-(hydroxymethyl)-1-butyl]-5-(1-azido-2-chloroethyl)uracil (12) was the most effective antiviral agent in the in vitro assays against DHBV (EC(50) = 0.31-1.55 microM) and HCMV (EC(50) = 3.1 microM). None of the compounds investigated showed any detectable toxicity to several stationary and proliferating host cells.     

Synthesis and antiviral activity of 1-cyclobutyl-5-(2-bromovinyl)uracil nucleoside analogues and related compounds.

A series of racemic (1 alpha (E), 2 beta, 3 alpha)-1-[2,3-bis(hydroxymethyl)cyclobutyl]-5-(2-halovinyl)uracils was synthesized and evaluated in cell culture. The bromovinyl, iodovinyl, and chlorovinyl analogues, 13, 15, and 16, respectively, are all potent inhibitors of varicella zoster virus (VZV), but are less inhibitory to the replication of human cytomegalovirus (HCMV) and herpes simplex viruses 1 and 2 (HSV-1, HSV-2). The excellent anti-VZV activities of 13, 15, and 16 coupled with their virtual inability to inhibit WI-38 cell growth indicate high in vitro therapeutic indices. VZV thymidine kinase readily converts these compounds to their respective monophosphates but not to their corresponding diphosphates. Compound 13a, the (1'R) enantiomer of the bromovinyl analogue 13, was also synthesized, and its potency is comparable to that of the racemate. A lower homologue 14, (1 alpha (E),2 beta, 3 alpha)-1-[2-hydroxy-3-(hydroxymethyl)cyclobutyl]-5- (2-bromovinyl)uracil, was found to be inactive against VZV, HCMV, HSV-1, and HSV-2.     

Synthesis and antiviral evaluation of 1,4-dioxane nucleoside analogues related to nucleoside dialdehydes

Since biologically active nucleoside 2',3'-dialdehydes exist as six-membered cyclic acetals (1) in solution, we have investigated the antiviral activity of some structurally similar 1,4-dioxane nucleoside analogues. By reacting 2',3'-seconucleoside tosylates with base, the guanine (10) and adenine (18) substituted (hydroxymethyl)dioxanes have been constructed. In addition, an unusual adenine-substituted divinyl ether (22) was synthesized via a base-catalyzed, double elimination of a 2',3'-di-O-tosyl-2',3'-secoadenosine. None of these compounds showed significant antiviral activity.     

Role of silent hepatitis B virus in chronic hepatitis B surface antigen(-) liver disease.

Despite a number of studies documenting hepatitis B virus (HBV) infection in the absence of hepatitis B surface antigen (HBsAg) a causal relationship between silent HBV infection and liver disease remain difficult to establish. In particular, both the prevalence and clinical significance of this observation are poorly understood. Why is HBV replication apparently so low in these patients? A number of studies have tried to elucidate the mechanism of HBsAg negative infections, and considerable data documenting HBV infectivity or reinfection in the absence of detectable HBsAg support the hypothesis that in some of these cases, HBV is undergoing low-level replication in the liver and this, in several situations including: (1) chronic liver disease, alcoholic liver disease, hepatocellular carcinoma; (2) viral reactivation following cancer chemotherapy or immunosuppression and (3) transmission via transfusion or from human serum to chimpanzees. In a recent study including 50 patients with chronic liver disease of unknown etiology we could detect serum HBV DNA by nested polymerase chain reaction (PCR) in 15/50 patients (50% at the cirrhosis stage) in the absence of HBsAg; in the liver of the 15 patients both HBcAg and/or HBsAg can be detected at very low-level. Viral host factors allowing HBV persistence in the absence of HBsAg can depend on several mechanisms. Coinfections with HCV can explain only a proportion of HBsAg(-) HBV infections. Secondly, HBV mutations in the core promotor region leading to a minimal viral replication, or mutations in the HBsAg-encoding region might explain the absence of serological recognition. Finally, it is possible that in some cases host immune mechanisms can maintain HBV infection in a latent state until transmission to another individual who subsequently develops a more active infection especially when immunosuppressive therapy is employed. Existence of HBsAg(-) HBV infections should be taken into account by the use of sensitive PCR tests for prevention of viral transmission in the settings of blood donations and organ transplants.     

5-Substituted-2,4-diamino-6-[2-(phosphonomethoxy)ethoxy]pyrimidines-acyclic nucleoside phosphonate analogues with antiviral activity

2,4-Diamino-6-hydroxypyrimidines substituted in position 5 by an allyl, benzyl, cyanomethyl, ethoxycarbonylmethyl, phenyl, cyclopropyl, or methyl group were prepared either by C5-alkylation or by formation of the pyrimidine ring by cyclization. Their alkylation with 2-[(diisopropoxyphosphoryl)methoxy]ethyl tosylate afforded N1- and O6-regioisomers that were separated and converted to the free phosphonic acids by treatment with bromotrimethylsilane followed by hydrolysis. Reaction of 2,4-diamino-6-[[(diisopropoxyphosphoryl)methoxy]ethoxy]pyrimidine with elemental bromine, N-chloro-, or N-iodosuccinimide gave the corresponding phosphorus-protected 5-bromo-, 5-chloro-, and 5-iodo derivatives, respectively. Their deprotection afforded 2,4-diamino-5-bromo- and -5-chloro-6-[2-(phosphonomethoxy)ethoxy]pyrimidines. 2,4-Diamino-5-methyl-6-[2-(phosphonomethoxy)ethoxy]pyrimidine was synthesized also by cross-coupling of the 5-bromo compound with AlMe(3), followed by deprotection. The compounds showed poor, if any, inhibitory activity against DNA viruses such as herpes simplex virus type 1 and type 2, cytomegalovirus, varicella-zoster virus, and vaccinia virus. In contrast, several 5-substituted 2,4-diaminopyrimidine derivatives markedly inhibited retrovirus replication in cell culture. The 5-methyl derivative was exquisitely inhibitory to human immunodeficiency virus and Moloney murine sarcoma virus-induced cytopathicity in cell culture (EC(50) approximately 0.00018 mumol/mL) but also cytostatic to CEM cell cultures. In contrast, the 5-halogen-substituted derivatives showed pronounced antiretroviral activity (EC(50) = 0.0023-0.0110 mumol/mL), comparable to that of the reference drugs adefovir and tenofovir, but were devoid of measurable toxicity at 0.3 mumol/mL.     

核苷类似物防治化疗后乙肝病毒再激活的临床疗效分析

目的回顾性分析核苷类似物(NAs)对恶性肿瘤合并慢性乙肝病毒(HBV)携带者化疗后HBV再激活的治疗效果及化疗前抗病毒用药对HBV再激活的预防作用。方法收集2006年1月―2011年12月本院住院肿瘤患者中进行细胞毒性药物化疗的非活动性乙肝表面抗原(HBsAg)携带者病例。对照组为规范细胞毒性药物化疗,观察化疗后乙肝病毒活跃情况和肝功能损害;预防组在化疗前1~2周使用NAs,根据具体情况持续使用NAs 6~12月,观察HBV再激活的情况和临床表现。结果共收集227例患者,化疗期间共出现67例(29.5%)HBV再激活。对照组102例患者中56例(54.9%)出现HBV再激活,其中19例患者发展为重型肝炎,9例死亡,2例转至外院行活体肝移植;预防组125例患者在使用NAs后有11例(8.8%)出现HBV再激活,其中5例发展为重型肝炎,2例死亡。两组再激活发生率有非常显著差异(χ2=57.4,P<0.001)。结论恶性肿瘤合并非活动性HBsAg携带者在接受细胞毒性药物化疗前应及时使用NAs抗病毒治疗,以减少HBV再激活的发生,从而改善临床预后。     

抗乙型肝炎病毒核苷（酸）类似物在妊娠和哺乳期妇女中应用的安全性

抗病毒治疗已被公认为治疗乙型肝炎的重要措施,但抗乙型肝炎病毒（HBV）核苷（酸）类似物在妊娠及哺乳期妇女中应用的安全性尚有许多争议。本文综述了近年来有关核苷（酸）类似物在妊娠及哺乳期妇女中应用的文献,为HBV感染的妊娠及哺乳期妇女的抗病毒治疗和母婴阻断提供更多证据。     

3种核苷类似物治疗慢性乙型肝炎的成本-效果分析

目的探讨3种核苷类似物治疗慢性乙型肝炎的经济效果。方法将268例患者分成3组,ADV组用阿德福韦酯10 mg,ETV组用恩替卡韦0.5 mg,LdT组用替比夫定600 mg,均为每天1次,疗程均为48周。进行疗效和不良反应观察,应用药物经济学成本-效果分析法进行评价。结果在HBV-DNA阴转率方面,ETV组和LdI组好于ADV组(P<0.01);在HBeAg阴转率和ALT复常率方面,3组差异无显著性(P>0.05);3组的不良反应差异无显著性(P>0.05);经济学方面,ADV组、ETV组、LdT组的成本-效果比分别是115.38、156.51、96.98,替比夫定优于阿德福韦酯和恩替卡韦。结论替比夫定组为优选方案。     

治疗慢性乙型肝炎的核苷类药物研究进展

慢性乙型肝炎是由乙型肝炎病毒(HBV)引起的一种世界性疾病,近年来,核苷类抗病毒药物的出现为慢性乙型肝炎的治疗开辟了一个新的领域。对核苷类抗乙肝病毒药物研究进展进行综述,为其进一步研究和临床应用提供参考。     

Synthesis and antiviral activity of enantiomeric forms of cyclobutyl nucleoside analogues.

The syntheses of the enantiomeric cyclobutyl guanine nucleoside analogues [1R-1 alpha, 2 beta, 3 alpha]- and [1S-1 alpha, 2 beta, 3 alpha]-2- amino-9-[2,3-bis(hydroxymethyl)cyclobutyl]-6H-purin-6-one (7 and 8, respectively) and the enantiomeric cyclobutyl adenine analogues [1R-1 alpha, 2 beta, 3 alpha]- and [1S-1 alpha, 2 beta, 3 alpha]-6-amino-9-[2,3-bis(hydroxymethyl) cyclobutyl]purine (9 and 10, respectively) are described. trans-3,3-Diethoxy-1,2-cyclobutanedicarboxylic acid (14) was coupled with R-(-)-2-phenylglycinol to provide a mixture of diastereomeric bis-amides, 15a and 15b, which was readily separated by crystallization. Conversion of each bis-amide to the corresponding diol enantiomer, 16a and 16b, respectively, was effected by a facile three-step sequence in high overall yield. Homochiral diol 16a was converted in a straightforward manner to 7 and 9, and homochiral diol 16b was similarly converted to the corresponding optical isomers 8 and 10. Compounds 7 and 9, which mimic the absolute configuration of natural nucleosides, are highly active against a range of herpesviruses in vitro while the isomers of opposite configuration, 8 and 10, are devoid of antiherpes activity. The corresponding triphosphates of 7 and 8 (7-TP and 8-TP) were prepared enzymatically. Compound 7-TP selectively inhibits HSV-1 DNA polymerase, compared to human (HeLa) DNA polymerase, while 8-TP is much less inhibitory than 7-TP against both types of enzymes. Compounds 7 and 9 are efficacious in a mouse cytomegalovirus model infection.     

Synthesis of new (+-)-3,5-dihydroxypentyl nucleoside analogues from 1-amino-5-(benzyloxy)pentan-3-ol and their antiviral evaluation

The synthesis and antiviral evaluation of a series of (+-)-3,5- dihydroxypentyl nucleoside analogues related to acyclic nucleoside antiviral agents are reported. All purine and pyrimidine nucleoside analogues described in this paper have been obtained from 1-amino-5-(benzyloxy)pentan-3-ol. A synthesis of this amine is reported from 1-(benzyloxy)but-3-ene after epoxidation and regiospecific diethylaluminum chloride catalyzed opening of the epoxide by trimethylsilyl cyanide. The compounds were tested in vitro in infected MRC5 and CEM cells. None of the compounds exhibited antiviral activity against HSV-1, HCMV, and HIV-1 with the exception of the guanine derivative 7, which inhibited the cytopathic effect of HSV-1 by 50% at 12.5 micrograms/mL.     

Thiazolides as novel antiviral agents. 1. Inhibition of hepatitis B virus replication

We report the syntheses and activities of a wide range of thiazolides [viz., 2-hydroxyaroyl-N-(thiazol-2-yl)amides] against hepatitis B virus replication, with QSAR analysis of our results. The prototypical thiazolide, nitazoxanide [2-hydroxybenzoyl-N-(5-nitrothiazol-2-yl)amide, NTZ] 1 is a broad spectrum antiinfective agent effective against anaerobic bacteria, viruses, and parasites. By contrast, 2-hydroxybenzoyl-N-(5-chlorothiazol-2-yl)amide 3 is a novel, potent, and selective inhibitor of hepatitis B replication (EC(50) = 0.33 μm) but is inactive against anaerobes. Several 4'- and 5'-substituted thiazolides show good activity against HBV; by contrast, some related salicyloylanilides show a narrower spectrum of activity. The ADME properties of 3 are similar to 1; viz., the O-acetate is an effective prodrug, and the O-aryl glucuronide is a major metabolite. The QSAR study shows a good correlation of observed EC(90) for intracellular virions with thiazolide structural parameters. Finally we discuss the mechanism of action of thiazolides in relation to the present results.